Semiconductor device, manufacturing method thereof, and electronic apparatus

ABSTRACT

A semiconductor device having a first semiconductor section including a first wiring layer at one side thereof; a second semiconductor section including a second wiring layer at one side thereof, the first and second semiconductor sections being secured together with the respective first and second wiring layer sides of the first and second semiconductor sections facing each other; a conductive material extending through the first semiconductor section to the second wiring layer of the second semiconductor section and by means of which the first and second wiring layers are in electrical communication; and an opening, other than the opening for the conductive material, which extends through the first semiconductor section to the second wiring layer.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.15/230,281, filed Aug. 5, 2016, which is a continuation of U.S. patentapplication Ser. No. 15/211,985, filed Jul. 15, 2016, which is acontinuation of U.S. patent application Ser. No. 14/451,809, filed Aug.5, 2014, now U.S. Pat. No. 9,419,041, which is a continuation of U.S.patent application Ser. No. 12/910,014, filed Oct. 22, 2010, now U.S.Pat. No. 8,848,075, which claims priority to Japanese Priority PatentApplication JP 2009-249327, filed in the Japan Patent Office on Oct. 29,2009, the entire disclosures of which are hereby incorporated herein byreference.

BACKGROUND OF THE INVENTION

The present invention relates to a semiconductor device, such as asolid-state image pickup device, a manufacturing method thereof, and anelectronic apparatus, such as a camera, including the solid-state imagepickup device.

As a solid-state image pickup device, an amplification type solid-stateimage pickup device represented by an MOS, such as complementary metaloxide semiconductor (CMOS), image sensor has been used. In addition, acharge transfer type solid-state image pickup device represented by acharge coupled device (CCD) image sensor has also been used. Thesesolid-state image pickup devices are widely used for a digital stillcamera, a digital video camera, and the like. In recent years, assolid-state image pickup devices mounted in mobile apparatuses, such asa camera mobile phone and a personal digital assistant (PDA), many MOSimage sensors have been used in view of a low power source voltage, alow power consumption, and the like.

The MOS solid-state image pickup device includes a peripheral circuitregion and a pixel array (pixel region) in which a plurality of unitpixels, each of which has a photodiode functioning as a photoelectricconversion portion and a plurality of pixel transistors, is arranged ina two-dimensional array. The pixel transistors are each formed of an MOStransistor, and the unit pixel has three transistors, that is, atransfer transistor, a reset transistor, and an amplifier transistor, orfour transistors including a selection transistor besides the abovethree transistors.

Heretofore, as the MOS solid-state image pickup device described above,various solid-state image pickup devices have been proposed in each ofwhich a semiconductor chip having a pixel region in which pixels arearranged and a semiconductor chip in which a logic circuit performing asignal processing is formed are electrically connected to each other toform one device. For example, in Japanese Unexamined Patent ApplicationPublication No. 2006-49361, a semiconductor module has been disclosed inwhich a backside illuminated image sensor chip having micro pads inindividual pixel cells and a signal processing chip which includes asignal processing circuit and micro pads are connected to each otherwith micro bumps interposed therebetween. In Japanese Unexamined PatentApplication Publication No. 2007-13089, a device has been disclosed inwhich a sensor chip including an image pick-up pixel portion, which is abackside illuminated MOS solid-state image pickup element, and a signalprocessing chip which includes a peripheral circuit performing signalprocessing are mounted on an interposer (intermediate substrate). InJapanese Unexamined Patent Application Publication No. 2008-130603, thestructure has been disclosed in which an image sensor chip, a thin filmcircuit board, and a logic circuit chip performing signal processing areprovided. In addition, the structure has also been disclosed in whichthe logic circuit chip is electrically connected to this thin filmcircuit board, and the thin film circuit board is electrically connectedto wire layers through a through-hole via from the rear surface of theimage sensor chip.

In Japanese Patent No. 4000507, a solid-state image pickup device hasbeen disclosed in which a solid-state image pickup element mounted on atransparent substrate is provided with a penetration electrode and iselectrically connected to a flexible circuit board therethrough.Furthermore, according to Japanese Unexamined Patent ApplicationPublication No. 2003-31785, a backside illuminated solid-state imagepickup device has been disclosed in which an electrode penetrating asupport substrate is provided.

As shown in Japanese Unexamined Patent Application Publication Nos.2006-49361 and 2007-13089 and Japanese Patent No. 2008-130603,techniques in which different types of circuits, such as an image sensorchip and a logic circuit, are mounted in combination have been variouslyproposed. In related techniques, the features thereof are thatfunctional chips used for this purpose are all in an almost finishedmaking state and are formed on one chip so as to be connectable to eachother by forming through substrate via holes.

As shown in the related solid-state image pickup device described above,an idea to form a semiconductor device by connecting between differenttypes of chips with a connection conductor penetrating substrates hasbeen proposed. However, since the connection hole has to be formed in athick substrate while the insulation is ensured, it has been believedthat the above idea is difficult to practically realize in considerationof cost economy of manufacturing processes necessary for machining theconnection hole and filling a connection conductor therein.

In addition, in order to form a small contact hole having a diameter ofapproximately 1 μm, the thickness of an upper chip has to be ultimatelyreduced. In this case, before the reduction in thickness is performed, acomplicated step, such as a step of adhering the upper chip to a supportsubstrate, is necessarily performed, and hence the cost is unfavorablyincreased. Furthermore, in order to fill a connection conductor in aconnection hole having a high aspect ratio, a CVD film, such as atungsten (W) film, having good covering properties has to be used as theconnection conductor, and hence a material for the connection conductoris limited.

In order to obtain a manufacturing process which has a superior economicefficiency and which can be easily applied to mass production, theaspect ratio of this connection hole has to be dramatically decreasedfor easy formation, and in addition, without using particular connectionhole machining, a machining technique used in a related wafermanufacturing process is preferably selected.

In addition, in a solid-state image pickup device and the like, it hasbeen desired that an image region and a logic circuit performing signalprocessing be formed to exhibit sufficient properties thereof and thatthe performance of the device be improved.

Besides the solid-state image pickup device, also in a semiconductordevice having different types of semiconductor integrated circuits, ithas been desired that the semiconductor integrated circuits be formed toexhibit sufficient properties thereof and that the performance of thesemiconductor device be improved.

Furthermore, in a device in which chips are connected to each other byadhering substrates at the circuit surfaces thereof, in order to performmounting connection, bonding pads and openings therefor necessarilyformed in the vicinity of an interface of the adhesion. However, whenthe thickness of the substrate is large, such as approximately severalhundreds of micrometers, high-cost mounting steps, such as formation ofdeep holes, formation of lead electrodes, and formation of solder balls,have to be performed.

In addition, since the adhesion surface has a fragile structure ascompared to that of another interlayer boundary, when the boundary ofthe adhesion surface is present under the bonding pad, a stressgenerated in bonding is concentrated on a fragile portion, and as aresult, cracks may be generated from the adhesion surface portion insome cases.

Furthermore, when semiconductor wafers are divided by dicing, cracks mayalso be generated from the adhesion surface between the substrates insome cases.

SUMMARY OF THE INVENTION

The present invention provides a semiconductor device, such as asolid-state image pickup device, which intends to improve itsperformance by exhibiting sufficient properties of each of semiconductorwafers laminated to each other, to improve mass productivity, and toreduce manufacturing cost, and a method for manufacturing thissemiconductor device. In addition, the invention provides an electronicapparatus, such as a camera, including the above solid-state imagepickup device.

One embodiment consistent with the present invention includes asemiconductor device comprising a first semiconductor section includinga first wiring layer at one side thereof, a second semiconductor sectionincluding a second wiring layer at one side thereof, the first andsecond semiconductor sections being secured together with the respectivefirst and second wiring layer sides of the first and secondsemiconductor sections facing each other, a conductive materialextending through the first semiconductor section to the second wiringlayer of the second semiconductor section and by means of which thefirst and second wiring layers are in electrical communication, and anopening, other than the opening for the conductive material, through thefirst semiconductor section to the second wiring layer.

Another embodiment consistent with the present invention includes asemiconductor substrate comprising an adhesive layer between the firstsemiconductor section and the second semiconductor section that securesthe first semiconductor section and second semiconductor sectiontogether.

Another embodiment consistent with the present invention includes asemiconductor substrate where the second wiring layer includes analuminum wire in contact with said conductive material.

Another embodiment consistent with the present invention includes asemiconductor substrate where the first wiring layer includes a copperwire and the conductive material is in contact with the copper wire.

Another embodiment consistent with the present invention includes asemiconductor substrate comprising a stress reduction film between thefirst semiconductor section and the second semiconductor section.

Another embodiment consistent with the present invention includes asemiconductor substrate comprising a photodiode in the firstsemiconductor section on a side of the first semiconductor sectionopposite the first multilayer wiring layer.

Another embodiment consistent with the present invention includes asemiconductor substrate comprising a suppression layer over thephotodiode.

Another embodiment consistent with the present invention includes asemiconductor substrate comprising an anti-reflection film over thesuppression layer.

Another embodiment consistent with the present invention includes asemiconductor substrate where the first semiconductor section and secondsemiconductor section are secured together by plasma bonding.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the steps offorming a first semiconductor section including a first wiring layer atone side thereof, forming a second semiconductor section including asecond wiring layer at one side thereof, securing the firstsemiconductor section to the second semiconductor section with therespective first and second wiring layer sides of the first and secondsemiconductor sections facing each other, providing a conductivematerial extending through the first semiconductor section to the secondwiring layer of the second semiconductor section by means of which thefirst and second wiring layers can be in electrical communication; andforming an opening, other than the opening for the conductive material,through the first semiconductor section which exposes the second wiringlayer.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device where the firstsemiconductor section and the second semiconductor section are securedtogether by means of adhesion.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device where the second wiringlayer includes an aluminum wire.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device where the conductivematerial is in contact with the aluminum wire.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device where the first wiringlayer includes a copper wire and the conductive material is in contactwith the copper wire.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the step ofproviding a stress reduction between the first semiconductor section andthe second semiconductor section.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the step offorming a photodiode in the first semiconductor section on a side of thefirst semiconductor section opposite the first multilayer wiring layer.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the step ofetching the side of the first semiconductor section furthest from thesecond semiconductor section such that a thin layer remains over thephotodiode.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the step offorming an anti-reflection film over the photodiode.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device where the firstsemiconductor section and second semiconductor section are securedtogether by plasma bonding.

Another embodiment consistent with the present invention includes asemiconductor device comprising a first semiconductor section includinga first wiring layer on one side and a device layer on the opposite sidethereof, a second semiconductor section including a second wiring layerat one side thereof, the first and second semiconductor sections beingsecured together with the respective first and second wiring layer sidesof the first and second semiconductor sections facing each other, afirst conductive material which extends through the device layer of thefirst semiconductor section to a connection point in the first wiringlayer of the first semiconductor section, and a second conductivematerial which extends through the first semiconductor section to aconnection point in the second wiring layer of the second semiconductorsection such that the first and second wiring layers are in electricalcommunication, and an opening, other than the openings for the first andsecond conductive materials, extending through the first semiconductorsection which exposes the second wiring layer.

Another embodiment consistent with the present invention includes asemiconductor device comprising the adhesive between the firstsemiconductor section that bonds the first semiconductor section andsecond semiconductor section.

Another embodiment consistent with the present invention includes asemiconductor device where the second wiring layer includes an aluminumwire.

Another embodiment consistent with the present invention includes asemiconductor device where the first conductive material and the secondconductive material electrically connect the aluminum wire in the secondwiring layer to a copper wire in the first wiring layer.

Another embodiment consistent with the present invention includes asemiconductor device comprising a stress reduction film between thefirst semiconductor section and the second semiconductor section.

Another embodiment consistent with the present invention includes asemiconductor device comprising a photodiode in the first semiconductorsection on a side of the first semiconductor section opposite the firstmultilayer wiring layer.

Another embodiment consistent with the present invention includes asemiconductor device comprising a suppression layer over the photodiode.

Another embodiment consistent with the present invention includes asemiconductor device comprising an anti-reflection film over thephotodiode.

Another embodiment consistent with the present invention includes asemiconductor device where the first semiconductor section and secondsemiconductor section are secured together by a plasma bond.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the steps offorming a first semiconductor section including a first wiring layer onone side and a device layer on the opposite side of the first wiringlayer, forming a second semiconductor section including a second wiringlayer at one side thereof, bonding the first semiconductor section tothe second semiconductor section with the respective first and secondwiring layer sides of the first and second semiconductor sections facingeach other, providing a first conductive material which extends throughthe device layer of the first semiconductor section to a connectionpoint in the first wiring layer of the first semiconductor section,providing a second conductive material which extends in parallel to thefirst conductive material and which extends through the firstsemiconductor section to a connection point in the second wiring layerof the second semiconductor section such that the first and secondwiring layers are in electrical communication, and forming an opening,other than the openings for the first and second conductive materials,extending through the first semiconductor section which exposes thesecond wiring layer.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the step ofproviding an adhesive layer between the first semiconductor and thesecond semiconductor section.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device where the second wiringlayer includes an aluminum wire.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device where the firstconductive material and second conductive material electrically connectthe aluminum wire in the second wiring layer to a copper wire in thefirst wiring layer.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the step ofproviding a stress reduction film between the first semiconductorsection and the second semiconductor section.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the step offorming a photodiode in the first semiconductor section on a side of thefirst semiconductor section opposite the first multilayer wiring layer.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the step ofetching the side of the first semiconductor section opposite themultilayer wiring layer such that a thin layer remains over thephotodiode.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including the step ofproviding an anti-reflection film over the photodiode.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device where the firstsemiconductor section and second semiconductor section are securedtogether by a plasma bond.

Another embodiment consistent with the present invention includes asemiconductor device including an optical unit, and an imaging unitincluding (a) a first semiconductor section including a first wiringlayer and a device layer on the first wiring layer, (b) a secondsemiconductor section including a second wiring layer at one sidethereof, the first and second semiconductor sections being securedtogether with the respective first and second wiring layer sides of thefirst and second semiconductor sections facing each other, (c) a firstconductive material which extends through the device layer of the firstsemiconductor section to a connection point in the first wiring layer ofthe first semiconductor section, (d) a second conductive material whichextends through the first semiconductor section to a connection point inthe second wiring layer of the second semiconductor section such thatthe first and second wiring layers are in electrical communication, and(e) an opening, other than the openings for the first and secondconductive materials, through the first semiconductor section whichexposes the second wiring layer.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device comprising a shutter unitbetween the optical unit and the imaging unit.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including an optical unitand an imaging unit including (a) a first semiconductor sectionincluding a first wiring layer on one side and a device layer on theopposite side thereof, (b) a second semiconductor section including asecond wiring layer at one side thereof, the first and secondsemiconductor sections secured together with the respective first andsecond wiring layer sides of the first and second semiconductor sectionsfacing each other, (c) a first conductive material which extends throughthe device layer of the first semiconductor section to a connectionpoint in the first wiring layer of the first semiconductor section, and(d) a second conductive material which extends through the firstsemiconductor section to a connection point in the second wiring layerof the second semiconductor section such that the first and secondwiring layers are in electrical communication, (e) an opening, otherthan the openings for the first and second conductive materials, throughthe first semiconductor section which exposes the second wiring layer.

Another embodiment consistent with the present invention includes amethod of manufacturing a semiconductor device including a shutter unitbetween the optical unit and the imaging unit.

According to the present invention, by using optimal process techniques,semiconductor wafers each having a circuit which exhibits sufficientproperties thereof can be laminated to each other; hence a semiconductordevice which has superior mass productivity and high performance can beobtained at a low cost. In addition, when the semiconductor device isapplied to a backside illuminated solid-state image pickup device, andthis solid-state image pickup device is used in an electronic apparatus,a high performance electronic apparatus can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural view showing one embodiment of an MOSsolid-state image pickup device consistent with the present invention;

FIG. 2A is a schematic view of a related solid-state image pickup deviceconsistent with the present invention;

FIGS. 2B and 2C are each a schematic view of a solid-state image pickupdevice consistent with the present invention;

FIG. 3 is a schematic structural view showing a portion of a solid-stateimage pickup device consistent with the present invention;

FIG. 4 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 5 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 6 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 7 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 8 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 9 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 10 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 11 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 12 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 13 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 14 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 15 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 16 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 17 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 18 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIGS. 19A and 19B are a schematic structural view showing thesemiconductor wafer and an enlarged view of a region that is consistentwith the present invention;

FIG. 20 is a schematic structural view that is consistent with thepresent invention that depicts a cross section including an electrodepad portion and a scribe line;

FIG. 21 is a schematic structural view consistent with the presentinvention that depicts a solid-state image pickup device;

FIG. 22 is a schematic structural view consistent with the presentinvention that depicts a solid-state image pickup device;

FIG. 23 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 24 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 25 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 26 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 27 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention;

FIG. 28 shows a method for manufacturing the solid-state image pickupdevice that is consistent with the present invention; and

FIG. 29 is a schematic structural view consistent with the presentinvention that depicts an electronic apparatus according to a fourthembodiment of the present invention.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 1 shows a schematic structure of an MOS solid-state image pickupdevice applied to a semiconductor device according to an embodiment ofthe present invention. This MOS solid-state image pickup device isapplied to a solid-state image pickup device of each embodiment. Asolid-state image pickup device 1 of this example includes a pixelregion (so-called pixel array) 3 in which pixels 2 each including aphotoelectric conversion portion are regularly arranged in atwo-dimensional array and a peripheral circuit portion on asemiconductor substrate (not shown) such as a silicon substrate. Thepixel 2 has, for example, a photodiode functioning as a photoelectricconversion portion and a plurality of pixel transistors (so-called MOStransistors). The plurality of pixel transistors may include threetransistors, such as a transfer transistor, a reset transistor, and anamplifier transistor. Alternatively, the plurality of pixel transistormay include four transistors by adding a selection transistor to theabove three transistor. Since the equivalent circuit of the unit pixelis the same as that of a general pixel, a detailed description isomitted. The pixel 2 may be formed as one unit pixel. In addition, thepixel 2 may have a shared pixel structure. This shared pixel structureis a structure in which a plurality of photodiodes share a floatingdiffusion forming a transfer transistor and transistors other than thetransfer transistor.

The peripheral circuit portion includes a vertical drive circuit 4,column signal processing circuits 5, a horizontal drive circuit 6, anoutput circuit 7, a control circuit 8, and the like.

The control circuit 8 receives an input clock and a data instructing anoperation mode or the like and outputs a data such as internalinformation of the solid-state image pickup device. That is, based on avertical synchronous signal, a horizontal synchronous signal, and amaster clock, the control circuit 8 generates a clock signal and acontrol signal which are used as the base of the operations of thevertical drive circuit 4, the column signal processing circuits 5, thehorizontal drive circuit 6, and the like. In addition, these signals areinput into the vertical drive circuit 4, the column signal processingcircuits 5, the horizontal drive circuit 6, and the like.

The vertical drive circuit 4 includes a shift register or the like,selects a pixel drive line, supplies a pulse thereto to drive pixels,and drives pixels on a row basis. That is, the vertical drive circuit 4sequentially performs selective scanning of pixels 2 on a row basis ofthe pixel region 3 in the vertical direction and supplies pixel signalsbased on signal charges generated in accordance with the amount of lightreceived in the photoelectric conversion portion, such as a photodiode,of each pixel 2 to the column signal processing circuits 5 throughvertical signal lines 9.

The column signal processing circuits 5 are each disposed, for example,for each line of the pixels 2 and each perform signal processing, suchas noise removal, on signals output from the pixels 2 on a line basisfor each pixel line. That is, the column signal processing circuit 5performs signal processing, such as correlated double sampling (CDS)which removes fixed pattern noise inherent in the pixel 2, signalamplification, and analog-to-digital (AD) conversion. An output stage ofthe column signal processing circuit 5 is connected to a horizontalsignal line 10 with a horizontal selection switch (not shown) interposedtherebetween.

The horizontal drive circuit 6 includes a shift register or the like,sequentially selects the column signal processing circuits 5 bysequentially outputting horizontal scanning pulses, so that therespective column signal processing circuits 5 are allowed to outputpixel signals to the horizontal signal line 10.

The output circuit 7 performs signal processing on signals sequentiallysupplied from the respective column signal processing circuits 5 throughthe horizontal signal line 10 and outputs the signals thus processed.For example, only buffering may be performed in some cases, or a blacklevel adjustment, a line variation correction, and various digitalsignal processing may be performed in some cases. Input/output terminals12 send and receive signals to and from the outside.

Next, the structure of the MOS solid-state image pickup device accordingto this embodiment will be described. FIG. 2A is a schematic viewshowing the structure of a related MOS solid-state image pickup device,and FIGS. 2B and 2C are schematic views each showing the structure ofthe MOS solid-state image pickup device according to this embodiment.

As shown in FIG. 2A, a related MOS solid-state image pickup device 151includes in one semiconductor chip 152, a pixel region 153, a controlcircuit 154, and a logic circuit 155 performing signal processing. Ingeneral, the pixel region 153 and the control circuit 154 form an imagesensor 156.

On the other hand, as shown in FIG. 2B, in an MOS solid-state imagepickup device 21 of this embodiment example, a pixel region 23 and acontrol circuit 24 are mounted on a first semiconductor chip portion 22,and a logic circuit 25 including a signal processing circuit whichperforms signal processing is mounted on a second semiconductor chipportion 26. This first semiconductor chip portion 22 and the secondsemiconductor chip portion 26 are electrically connected to each otherto form the MOS solid-state image pickup device 21 as one semiconductorchip.

As shown in FIG. 2C, in an MOS solid-state image pickup device 27 ofanother embodiment example of the present invention, a pixel region 23is mounted on a first semiconductor chip portion 22, and a controlcircuit 24 and a logic circuit 25 including a signal processing circuitare mounted on a second semiconductor chip portion 26. This firstsemiconductor chip portion 22 and the second semiconductor chip portion26 are electrically connected to each other to form the MOS solid-stateimage pickup device 27 as one semiconductor chip.

The MOS solid-state image pickup devices of the above embodimentexamples each have the structure in which different types ofsemiconductor chips are laminated to each other, and as described later,a manufacturing method of the above solid-state image pickup device andthe structure obtained thereby have advantages.

In the following embodiment examples, a solid-state image pickup deviceaccording to an embodiment of the present invention and a manufacturingmethod thereof will be described.

With reference to FIG. 3 and FIGS. 4 to 20, as a semiconductor deviceaccording to a first embodiment example of the present invention, abackside illuminated MOS solid-state image pickup device will bedescribed together with a manufacturing method thereof.

FIG. 3 is a schematic cross-sectional structural view (completed view)including an electrode pad portion 78 of a solid-state image pickupdevice of this embodiment example. In a solid-state image pickup device81 of this embodiment example, a first semiconductor chip portion 22including a pixel array (hereinafter referred to as “pixel region”) 23and a control circuit 24 and a second semiconductor chip portion 26 onwhich a logic circuit 25 is mounted are laminated in a verticaldirection so as to be electrically connected to each other.

With reference to FIGS. 4 to 19, a method for manufacturing thesolid-state image pickup device 81 of this embodiment example will bedescribed.

In the first embodiment example, as shown in FIG. 4, first, asemi-finished image sensor, that is, a semi-finished pixel region 23 anda semi-finished control circuit 24, is formed on a region of a firstsemiconductor wafer (hereinafter referred to as “first semiconductorsubstrate”) 31 which is to be formed into each chip portion. That is, onthe region of the first semiconductor substrate 31 formed of a siliconsubstrate on which each chip portion is formed, a photodiode (PD)functioning as a photoelectric conversion portion of each pixel isformed, and source/drain regions 33 for each pixel transistor are formedin a semiconductor well region 32. The semiconductor well region 32 isformed by implanting a first conductive impurity, such as a p-typeimpurity, and the source/drain regions 33 are formed by implanting asecond conductive impurity, such as an n-type impurity. The photodiode(PD) and the source/drain regions 33 of each pixel transistor are formedby ion implantation performed from the substrate surface.

The photodiode (PD) is formed of an n-type semiconductor region 34 and ap-type semiconductor region 35 located at a substrate surface side. Gateelectrodes 36 are formed on a substrate surface on which pixels areformed with a gate insulating film interposed therebetween to form pixeltransistors Tr1 and Tr2 with the source/drain regions 33. In FIG. 4, aplurality of pixel transistors is represented by the two pixeltransistors Tr1 and Tr2. The pixel transistor Tr1 adjacent to thephotodiode (PD) corresponds to a transfer transistor and one of thesource/drain regions thereof corresponds to a floating diffusion (FD).Unit pixels 30 are separated from each other by an element isolationregion 38.

In addition, at a control circuit 24 side, MOS transistors forming acontrol circuit are formed on the first semiconductor substrate 31. InFIG. 3, the MOS transistors forming the control circuit 24 arerepresented by MOS transistors Tr3 and Tr4. The MOS transistors Tr3 andTr4 each include n-type source/drain regions 33 and a gate electrode 36formed on a gate insulating film.

Next, after a first-layer interlayer insulating film 39 is formed on thesurface of the first semiconductor substrate 31, connection holes areformed in the interlayer insulating film 39, and connection conductors44 connected to necessary transistors are formed. When connectionconductors having different heights are formed, a first insulating thinfilm 43 a, such as a silicon oxide film, is formed on the entire surfaceincluding upper surfaces of the transistors, and a second insulatingthin film 43 b, such as silicon nitride film, functioning as an etchingstopper is laminated on the first insulating thin film 43 a. Thefirst-layer interlayer insulating film 39 is formed on this secondinsulating thin film 43 b. In order to form the first-layer interlayerinsulating film 39, for example, after a plasma oxide film (P-SiO film)is formed to have a thickness of 10 to 150 nm, a non-doped silicateglass (NSG) film or a phosphosilicate glass (PSG) film is formed to havea thickness of 50 to 1,000 nm. Subsequently, a dTEOS film having athickness of 100 to 1,000 nm is formed, and a plasma oxide film (P-SiOfilm) is formed to have a thickness of 50 to 200 nm, so that thefirst-layer interlayer insulating film 39 is formed.

Subsequently, connection holes having different depths are selectivelyformed in the first-layer interlayer insulating film 39 to the secondinsulating thin film 43 b functioning as an etching stopper. Next, thefirst insulating thin film 43 a and the second insulating thin film 43b, each of which have a uniform thickness at the respective portions,are selectively etched to form connection holes so as to communicatewith the connection holes described above. Subsequently, the connectionconductors 44 are filled in the respective connection holes.

In addition, after the second insulating thin film 43 b is formed, aninsulating spacer layer 42 isolating a desired region in thesemiconductor well region 32 of the first semiconductor substrate 31 isformed. The insulating spacer layer 42 is formed in such a way thatafter the second insulating thin film 43 b is formed, an opening isformed at a desired position of the first semiconductor substrate 31from the rear surface side thereof, and an insulating material is thenfilled in the opening. This insulating spacer layer 42 is formed in aregion surrounding an inter-substrate wire 68 shown in FIG. 3.

Next, a plurality of layers, that is, three layers of copper wires 40 inthis example, are formed to be connected to the connection conductors 44with the interlayer insulating films 39 interposed therebetween, so thata multilayer wire layer 41 is formed. In general, each copper wire 40 iscovered with a barrier metal layer (not shown) to prevent Cu diffusion.The barrier metal layer may be formed of a SiN film or a Sic film havinga thickness of 10 to 150 nm. In addition, for a second-layer interlayerinsulating film 39 and so forth, a dTEOS film (silicon oxide film formedby a plasma CVD method) having a thickness of 100 to 1,000 nm may beused. When the interlayer insulating films 39 and the copper wires 40are alternately formed with the barrier metal layers interposedtherebetween, the multilayer wire layer 41 is formed. In this embodimentexample, although the multilayer wire layer 41 is formed using thecopper wires 40 by way of example, another metal material may also beused as a metal wire.

By the steps described above, the semi-finished pixel region 23 and thesemi-finished control circuit 24 are formed on the first semiconductorsubstrate 31.

In addition, as shown in FIG. 5, on a region of a second semiconductorsubstrate (semiconductor wafer) 45 formed of, for example, of siliconwhich is to be formed into each chip portion, a semi-finished logiccircuit 25 including a signal processing circuit for signal processingis formed. That is, on a p-type semiconductor well region 46 of thesecond semiconductor substrate 45 located at a surface side, a pluralityof MOS transistors forming the logic circuit 25 is formed so as to beisolated from each other by an element isolation region 50. In thiscase, the plurality of MOS transistors is represented by MOS transistorsTr6, Tr7, and Tr8. The MOS transistors Tr6, Tr7, and Tr8 are each formedof n-type source/drain regions 47 and a gate electrode 48 provided on agate insulating film. The logic circuit 25 may be formed of CMOStransistors.

Next, after a first-layer interlayer insulating film 49 is formed on thesurface of the second semiconductor substrate 45, connection holes areformed in the interlayer insulating film 49, and connection conductors54 to be connected to necessary transistors are formed. When connectionconductors 54 having different heights are formed, as described above, afirst insulating thin film 43 a, such as a silicon oxide film, and asecond insulating thin film 43 b, such as a silicon nitride film,functioning as an etching stopper are laminated on the entire surfaceincluding upper surfaces of the transistors. The first-layer interlayerinsulating film 49 is formed on this second insulating thin film 43 b.In addition, connection holes having different depths are selectivelyformed in the first-layer interlayer insulating film 49 to the secondinsulating thin film 43 b functioning as an etching stopper. Next, thefirst insulating thin film 43 a and the second insulating thin film 43b, each of which have a uniform thickness at the respective portions,are selectively etched to form connection holes so as to communicatewith the connection holes described above. Subsequently, the connectionconductors 54 are filled in the respective connection holes.

Next, the formation of the interlayer insulating film 49 and theformation of a metal wire layer are repeatedly performed, so that amultilayer wire layer 55 is formed. In this embodiment, after threelayers of copper wires 53 are formed in a manner similar to that of theformation step of the multilayer wire layer 41 on the firstsemiconductor substrate 31, an aluminum wire 57 is formed as the topmostlayer. The aluminum wire 57 is formed such that after the interlayerinsulating film 49 is formed on the topmost layer of the copper wire 53,the interlayer insulating film 49 is etched so that desired positions ofthe upper portion of the topmost layer of the copper wire 53 areexposed, thereby forming connection holes. Subsequently, on a regionincluding the insides of the connection holes, there is formed amultilayer film of TiN (lower layer)/Ti (upper layer) functioning as abarrier metal layer 56 having a thickness of 5 to 10 nm or a multilayerfilm of TaN (lower layer)/Ta (upper layer) having a thickness of 10 to100 nm. Next, an aluminum film having a thickness of 500 to 2,000 nm isformed to cover the connection holes and is then patterned into adesired shape, thereby forming the aluminum wire 57. Furthermore, abarrier metal layer 58 which is necessary in a subsequent step is formedon the aluminum wire 57. This barrier metal layer 58 may have acomposition similar to that of the barrier metal layer 56 which isformed under the aluminum wire 57.

In addition, the interlayer insulating film 49 is formed to cover thealuminum wire 57 together with the barrier metal layer 58 providedthereon. The interlayer insulating film 49 on the aluminum wire 57 maybe formed such that, for example, after a high density plasma oxide film(HDP film) or a plasma oxide film (P-SiO film) is formed to have athickness of 500 to 2,000 nm, a p-SiO film having a thickness of 100 to2,000 nm is further formed on the film described above. As a result, themultilayer wire layer 55 is formed which includes the three layers ofthe copper wires 53 and the aluminum wire 57 formed as the topmost layerwith the interlayer insulating films 49 interposed therebetween.

In addition, on the multilayer wire layer 55, a stress correction film59 is formed which reduces a stress generated when the firstsemiconductor substrate 31 and the second semiconductor substrate 45 areadhered to each other. The stress correction film 59 may be formed, forexample, from a P-SiN film or a plasma oxynitride film (P-SiON film)having a thickness of 100 to 2,000 nm.

By the steps described above, the semi-finished logic circuit 25 isformed on the second semiconductor substrate 45.

Next, as shown in FIG. 6, the first semiconductor substrate 31 and thesecond semiconductor substrate 45 are secured to each other so that themultilayer wire layer 41 faces the multilayer wire layer 55. Theadhesion is performed using an adhesive. When the adhesion is performedusing an adhesive, an adhesive layer 60 is formed on one bonding surfaceof the first semiconductor substrate 31 or the second semiconductorsubstrate 45, and with this adhesion layer 60, the two substrates areoverlapped with and secured to each other. In this embodiment, after thefirst semiconductor substrate 31 on which the pixel region is formed isdisposed at an upper layer side, and the second semiconductor substrate45 is disposed at a lower layer side, the adhesion is performedtherebetween.

In addition, in this embodiment, the first semiconductor substrate 31and the second semiconductor substrate 45 are adhered to each other withthe adhesive layer 60 interposed therebetween is described by way ofexample; however, adhesion may also be performed by plasma bonding. Inthe case of the plasma bonding, a plasma TEOS film, a plasma SiN film, aSiON film (block film), a SiC film, or the like is formed on a bondingsurface of each side of the first semiconductor substrate 31 and thesecond semiconductor substrate 45. The bonding surfaces each providedwith one of the above films are processed by a plasma treatment and areoverlapped with each other, and subsequently, the two semiconductorsubstrates are secured to each other by an annealing treatment. Theadhesion treatment is preferably performed by a low temperature processat a temperature of 400° C. or less in which wires and the like are notadversely influenced.

In addition, the first semiconductor substrate 31 and the secondsemiconductor substrate 45 are laminated and adhered to each other, sothat a laminate 81 a including the two different types of substrates isformed.

Next, as shown in FIG. 7, grinding and polishing are performed from arear surface 31 b side of the first semiconductor substrate 31 to reducethe thickness thereof. The thickness is reduced so that a thin layer isprovided on the photodiode (PD). As the first semiconductor substrate 31when a semiconductor substrate in which a heavily doped p-type impuritylayer is formed as an etching stopper layer (not shown) is used, byetching the substrate to the etching stopper layer, the thickness of thesemiconductor substrate can be uniformly reduced. After the thicknessreduction is performed, a p-type semiconductor layer is formed on therear surface of the photodiode (PD) to suppress a dark current. Althoughthe thickness of the first semiconductor substrate 31 is approximately600 μm, the thickness thereof is reduced to approximately 3 to 5 μm.Heretofore, the thickness reduction described above has been performedafter a support substrate which is separately prepared is adhered to themultilayer wire layer 41 on the first semiconductor substrate 31.However, in this embodiment, the thickness reduction of the firstsemiconductor substrate 31 is performed by also using the secondsemiconductor substrate 45 on which the logic circuit 25 is formed as asupport substrate. The rear surface 31 b of this first semiconductorsubstrate 31 functions as a light incident surface when a backsideilluminated solid-state image pickup device is formed.

Next, as shown in FIG. 8, an anti-reflection film 61 is formed on therear surface of the first semiconductor substrate 31. Theanti-reflection film 61 may be formed using a TaO₂ or a HfO₂ film havinga thickness of 5 to 100 nm. The anti-reflection film 61 formed of TaO₂or HfO₂ has a pinning effect at an interface with the firstsemiconductor substrate 31, and by this anti-reflection film 61, a darkcurrent generated at the rear surface side interface of the firstsemiconductor substrate 31 can be suppressed. When an annealingtreatment is performed after the anti-reflection film 61 is formed, theanti-reflection film 61 formed of TaO₂ or HfO₂ is dehydrated. Since theanti-reflection film 61 is dehydrated by this annealing treatment, filmpeeling of a HDP film or the like which is formed in a subsequent stepcan be prevented. Subsequently, on the anti-reflection film 61, an HDPfilm or a P-SiO film having a thickness of 100 to 1,500 nm is formed asa first-layer insulating film 62. Next, after the first-layer insulatingfilm 62 is formed, an opening is formed in a desired region thereof soas to expose the rear surface side of the first semiconductor substrate31, and a shading film 63 covering the opening is formed in a desiredregion except for an upper portion of the region in which the photodiode(PD) is formed. The shading film 63 may be formed of tungsten (W) or Al,may be formed as a multilayer film of W/Ti (or Ta or TiN), or may beformed as a multilayer film of Al/Ti (or Ta or TiN). In this case alower layer film is formed to have a thickness of 50 to 500 nm, and anupper layer film is then formed to have a thickness of 5 to 100 nm.

Next, as shown in FIG. 9, an insulating film 62 is further formed usinga SiO₂ film on the shading film 63, and subsequently, a first grooveportion 64 is formed in a desired region inside the insulating spacerlayer 42 from the side of the first semiconductor substrate 31 which isthe upper substrate. This first groove portion 64 is formed to have adepth not to reach the first semiconductor substrate 31.

Next, as shown in FIG. 10, in a desired bottom region of the firstgroove portion 64, an opening is formed which penetrates the adhesionsurface between the first semiconductor substrate 31 and the secondsemiconductor substrate 45 to a depth which is very close to thealuminum wire 57 formed above the second semiconductor substrate 45. Asa result, a second groove portion 65 is formed. Next, in a mannersimilar to that described above, in the desired bottom region of thefirst groove portion 64, an opening is formed to a depth which is veryclose to the topmost layer of the copper wire 40 (at a bottommost sidein FIG. 10) of the multilayer wire layer 41 formed on the firstsemiconductor substrate 31. As a result, a third groove portion 66 isformed. Since the second groove portion 65 and the third groove portion66 are formed after the thickness of the first semiconductor substrate31 is reduced, the aspect ratio is decreased, and hence, the grooveportions can be each formed as a fine hole.

In another embodiment consistent with the present invention shown inFIG. 10B, a single opening 65 is formed that penetrates the adhesionsurface between the first semiconductor substrate 31 and the secondsemiconductor substrate 45 to a depth which is very close to thealuminum wire 57 above the second semiconductor substrate 45 and alsothe top most copper wire 40. For this embodiment, the manufacturingsteps are similar to the manufacturing process including two openings,with only the references to the second opening 64 being omitted.

Next, on a region including sidewalls and bottom portions of the firstto the third groove portions 64, 65, and 66 an insulating layer 67 of aSiO₂ film is formed and is then etched back, so that the insulatinglayer 67 is allowed to remain only on the sidewalls of the first to thethird groove portions as shown in FIG. 11. Subsequently, the bottomportions of the second and the third groove portions 65 and 66 arefurther removed by etching, so that in the second groove portion 65, thealuminum wire 57 (to be exact, the barrier metal 58 on the aluminumwire) is exposed, and in the third groove portion 66, the topmost-layercopper wire 40 is exposed. Accordingly, the third groove portion 66 isformed as a connection hole which exposes the copper wire 40 formedabove the first semiconductor substrate 31, and the second grooveportion 65 is formed as a through substrate via hole which penetratesthe first semiconductor substrate 31 and which exposes the aluminum wire57 formed above the second semiconductor substrate 45.

At this stage, steps of forming an on-chip color filter and an on-chiplens, which are parts of a process for manufacturing a pixel array, arenot carried out, and hence this process is not completed. In addition,the connection hole formed on the copper wire 40 and the penetrationconnection hole formed on the aluminum wire 57 can be machined andformed by appropriately using related wafer processes. Furthermore, alsoin the logic circuit 25, although the optimum topmost-layer metal wireis formed in view of a circuit technique, the entire process for thelogic circuit 25 is not completed. As described above, since thedifferent types of semi-finished substrates are adhered to each other,compared to the case in which different types of finished substrates areadhered to each other, the manufacturing cost can be reduced.

Subsequently, as shown in FIG. 12 connection conductors composed ofcopper or the like are formed in the first to the third groove portions64, 65, and 66, so that the inter-substrate wire 68 is formed. In thisembodiment example, since the second groove portion 65 and the thirdgroove portion 66 are formed inside the first groove portion 64, theconnection conductors (inter-substrate wire 68) formed in the secondgroove portion 65 and the third groove portion 66 are electricallyconnected to each other. Hence, the copper wire 40 formed in themultilayer wire layer 41 on the first semiconductor substrate 31 and thealuminum wire 57 formed in the multilayer wire layer 55 on the secondsemiconductor substrate 45 are electrically connected to each other. Inaddition, in this case, since the barrier metal layer 58 is formed onthe aluminum wire 57 formed in the multilayer wire layer 55 on thesecond semiconductor substrate 45, even if the inter-substrate wire 68is formed of copper, the diffusion thereof can be prevented. Theinsulating layer 67 is formed on the portions of the second grooveportion 65 and the third groove portion 66 which penetrate the firstsemiconductor substrate 31. Accordingly, the inter-substrate wire 68 andthe first semiconductor substrate 31 are not electrically connected toeach other. In addition, in this embodiment, since the inter-substratewire 68 is formed in the region of the insulating spacer layer 42 formedin the first semiconductor substrate 31, by this structure, theinter-substrate wire 68 and the first semiconductor substrate 31 arealso prevented from being electrically connected to each other.

In the process for forming the inter-substrate wire 68 of thisembodiment, the first to the third groove portions 64, 65, and 66 areseparately formed in different steps and a damascene method is used tofill copper; however, the process is not limited thereto. Variousmodifications may be performed as long as the inter-substrate wire 68 isformed which electrically connects the copper wire 40 of the multilayerwire layer 41 on the first semiconductor substrate 31 to the aluminumwire 57 of the multilayer wire layer 55 on the second semiconductorsubstrate 45.

In this embodiment, the case in which the insulation between theinter-substrate wire 68 and the first semiconductor substrate 31 isperformed by the insulating layer 67 and the insulating spacer layer 42is descried by way of; however, the insulation may be preformed by oneof them. When the insulating spacer layer 42 is not formed, since theregion for the insulating spacer layer 42 is not necessary, thereduction in pixel area and/or the increase in area of the photodiode(PD) can be performed.

Next, as shown in FIG. 13, a cap film 72 is formed so as to cover anupper portion of the inter-substrate wire 68. This cap film 72 may beformed using a SiN film or a SiCN film having a thickness of 10 to 150nm. Subsequently, an opening portion is formed in the insulating film 62above the photodiode (PD), and a waveguide material film 69 is formed ona desired region including the opening portion described above. For thewaveguide material film 69 SiN may be used, and by the waveguidematerial film 69 formed in the opening portion, a waveguide path 70 isformed. Since the waveguide path 70 is formed, light incident from therear surface side of the first semiconductor substrate 31 is efficientlycondensed to the photodiode (PD). Subsequently, a planarization film 71is formed on the entire surface including the waveguide material film69.

In this embodiment, although the cap film 72 and the waveguide materialfilm 69 provided thereon are formed in separate steps, the waveguidematerial film 69 may also be used as the cap film 72. In addition, inthis embodiment example, although the case in which the waveguide path70 is formed at the light incident surface side of the photodiode (PD)is described by way of example, the waveguide path 70 may not be formedin some cases. Furthermore, in this embodiment, although the case inwhich the inter-substrate wire 68 is formed after the shading film 63 isformed is described by way of example, before the shading film 63 isformed, the through substrate via hole and the connection hole areformed, and subsequently, the inter-substrate wire 68 may then beformed. In this case, since the inter-substrate wire 68 is covered withthe shading film 63, the shading film 63 may also be used as the capfilm for the inter-substrate wire 68. According to the structure asdescribed above, the number of manufacturing steps can be reduced.

Next, as shown in FIG. 14 red (R), green (G), and blue (B) on-chip colorfilters 73 are formed on the planarization film 71 so as to correspondto the individual pixels. The on-chip color filter 73 can be formed onupper portions of photodiodes (PDs) forming a desired pixel array by thesteps of forming an organic film containing a pigment or a dye having adesired color and patterning the film thus formed. Subsequently, a filmof an on-chip lens material 74 a is formed on a pixel array regionincluding the upper portion of the on-chip color filters 73. As theon-chip lens material 74 a an organic film or an inorganic film of SiO,SiN, SiON, or the like may be formed to have a thickness of 3,000 to4,500 nm.

Next, as shown in FIG. 15, after a resist film 75 for an on-chip lens isformed on the on-chip lens material 74 a in regions corresponding to theindividual pixels to have a thickness of 300 to 1,000 nm, an etchingtreatment is performed. Accordingly, the shape of the resist film 75 foran on-chip lens is transferred to the on-chip lens material 74 a, and asshown in FIG. 16, an on-chip lens 74 is formed on the individual pixels.Subsequently, the oxide films, such as the insulating film 62, formed onthe first semiconductor substrate 31 are etched by a CF₄-based gas (flowrate: 10 to 200 sccm), so that the first semiconductor substrate 31 isexposed.

Next, as shown in FIG. 17, a resist film 76 having an opening at theelectrode pad portion 78 shown in FIG. 3 is formed on the on-chip lens74. As shown in FIG. 17, this resist film 76 is formed so that the endportion of the opening is located closer to the pixel side than the endportion of the on-chip lens 74.

Next, an etching treatment is performed under desired etching conditionsusing the resist film 76 as a mask. Accordingly, as shown in FIG. 18,etching is started from the side of the first semiconductor substrate 31which is the topmost substrate, and a through substrate opening portion77 is formed which penetrates the first semiconductor substrate 31 andthe bonding surface between the first semiconductor substrate 31 and thesecond semiconductor substrate 45. In addition, the through substrateopening portion 77 is formed to expose the aluminum wire 57 formed inthe multilayer wire layer 55 on the second semiconductor substrate 45which is the bottommost substrate. This etching step is performed usinga SF₆/O₂-based gas (flow rate of SF₆: 50 to 500 sccm, and flow rate ofO₂: 10 to 300 sccm) for 1 to 60 minutes, so that the first semiconductorsubstrate 31 can be etched away. Subsequently, by an etching treatmentperformed for 1 to 100 minutes using a CF₄-based gas (flow rate: 10 to150 sccm), the oxide films and the like formed to the aluminum wire 57can be etched away.

The aluminum wire 57 thus exposed is used as the electrode pad portion78 which is used for connection to an external wire. Hereinafter, thealuminum wire 57 thus exposed is called the electrode pad portion 78. Aplurality of the electrode pad portions 78 is preferably formed alongeach of three or four external sides of the pixel region formed in eachchip.

In addition, the laminate 81 a formed by laminating the twosemiconductor substrates as shown in FIG. 18 is subsequently dividedinto chips by dicing, so that the solid-state image pickup device 81 ofthis embodiment is completed. In this embodiment, when the electrode padportion 78 is exposed, groove portions each functioning as a crackstopper used in chip division can be formed at the same time.

FIG. 19A is a schematic structural view of the laminate 81 a formed ofthe first semiconductor substrate 31 and the second semiconductorsubstrate 45 before being divided into chips, and FIG. 19B is anenlarged view of a chip portion 91 shown in a region a of FIG. 19A. Inaddition, FIG. 20 is a schematic cross-sectional view along the lineXX-XX of FIG. 19B and shows a region including the electrode pad portion78 formed in one chip portion 91 and a scribe line Ls adjacent to theelectrode pad portion 78.

As shown in FIG. 19B, a plurality of chip portions 91 formed on thefirst semiconductor substrate 31 (second semiconductor substrate 45) aredivided along the scribe lines Ls each shown by a solid line. Inaddition, in this embodiment, as shown in FIG. 20, in a region betweenadjacent chips and at two sides of the scribe line Ls, groove portions89 are simultaneously formed when an opening step to expose theelectrode pad portion 78 is performed. These groove portions 89 eachfunction as a crack stopper s.

In this embodiment, as shown in FIG. 20, after the groove portions 89each functioning as the crack stopper s are formed at the two sides ofthe scribe line Ls, dividing is performed along the scribe line Ls by adicing blade 90. Accordingly, at a fragile surface, such as the adhesionsurface between the first semiconductor substrate 31 and the secondsemiconductor substrate 45, cracks can be prevented from beingpropagated in dicing operation. Hence, cracks are prevented from beinggenerated in the chip portion 91 when it is divided.

As shown in FIG. 3, a bonding wire 79 is connected to the electrode padportion 78, so that each chip 91 thus divided can be connected to anexternal wire of a mounting substrate by this bonding wire 79. Inaddition, since the external wire is electrically connected to theelectrode pad portion 78, the multilayer wire layers 41 and 55 on thefirst and the second semiconductor substrates 31 and 45, respectively,which are connected to each other by the inter-substrate wire 68 arealso electrically connected to the external wire.

In the solid-state image pickup device according to the firstembodiment, although the case in which the bonding wire 79 is connectedto the electrode pad portion 78 is described by way of example, theelectrode pad portion 78 and the external wire may be connected to eachother by using a solder bump. Depending on a user's request, the bondingwire or the solder bump may be selected.

In the first embodiment, inspection of the solid-state image pickupdevices in a semiconductor wafer state is performed using the electrodepad portions 78. In addition, two inspections, that is, an inspection ina wafer state and an inspection in a final module state obtained by chipdivision, are performed.

In the solid-state image pickup device according to the first embodimentand the manufacturing method thereof, the pixel region 23 and thecontrol circuit 24 are formed on a chip portion of the firstsemiconductor substrate 31, and the logic circuit 25 performing signalprocessing is formed on a chip portion of the second semiconductorsubstrate 45. Since the pixel array function and the logic function areformed on different chip portions, optimal process techniques may berespectively used for the pixel array and the logic circuit. Hence, therespective performances of the pixel array and the logic circuit can besufficiently obtained, and as a result, a high performance solid-stateimage pickup device can be provided.

When the structure shown in FIG. 2C is used, the pixel region 23receiving light may only be formed at the semiconductor chip portion 22side, and the control circuit 24 for the pixel region 23 and the logiccircuit 25 may be separately formed in the second semiconductor chipportion 26. Accordingly, optimal process techniques necessary for therespective functional chips can be independently selected, and inaddition, the area of the product module can also be reduced.

Since the pixel array and the logic circuit can be mounted incombination by related wafer process techniques which have been commonlyused, the manufacturing can be easily performed.

In addition, in this embodiment, after the first semiconductor substrate31 on which the pixel region 23 and the control circuit 24 are providedin a semi-finished making state and the second semiconductor substrate45 on which the logic circuit 25 is provided in a semi-finished makingstate are adhered to each other, the thickness of the firstsemiconductor substrate 31 is reduced. That is, the second semiconductorsubstrate 45 is used as a support substrate when the thickness of thefirst semiconductor substrate 31 is reduced. Hence, the number ofconstituent members can be reduced, and the number of manufacturingsteps can be reduced. Furthermore, since the through substrate via hole(second groove portion 65) and the connection hole (third groove portion66) are formed after the thickness reduction is performed, the aspectratio of each hole is decreased, and highly precise connection holes canbe formed. In addition, since the inter-substrate wire 68 is filled inthe through substrate via hole and the connection hole, each having alow aspect ratio, as a matter of course, a metal material, such astungsten (W), having superior covering properties can be used, and inaddition, a metal material, such as copper (Cu), having inferiorcovering properties may also be used. That is, a connection conductormaterial is not particularly limited. Hence, the electrical connectionof the logic circuit to the pixel region and the control circuit can beperformed with high accuracy. Accordingly, a high performancesolid-state image pickup device can be manufactured which improves massproductivity and reduces manufacturing cost.

Furthermore, in this embodiment, the through substrate opening portion77 formed to expose the electrode pad portion 78 penetrates the bondingsurface between the first semiconductor substrate 31 and the secondsemiconductor substrate 45, and the electrode pad portion 78 is formedof the wire above the second semiconductor substrate 45 which is thelower substrate. Accordingly, the electrode pad portion 78 is formed ata lower layer than the bonding surface between the first semiconductorsubstrate 31 and the second semiconductor substrate 45 which isconsidered to be a fragile surface. Hence when the bonding wire 79 ispressed to the electrode pad portion 78, a bonding stress applied to thebonding surface which is a fragile surface can be reduced. As a result,in wire bonding, cracks are prevented from being generated from thefragile bonding surface (bonding surface between the first semiconductorsubstrate 31 and the second semiconductor substrate 45 in thisembodiment).

In this embodiment, although the two semiconductor wafers are laminatedto each other, the present invention may also be applied to thestructure in which at least two semiconductor wafers are laminated toeach other. In this case, a through substrate opening portion is formedso as to expose a wire of a wire layer above the bottommostsemiconductor water, and the wire thus exposed is used as an electrodepad portion. Accordingly, when the electrode pad portion and an externalwire are connected to each other, the generation of stress at a fragilebonding surface between the substrates can be suppressed.

In addition, as in this embodiment, in the backside illuminatedsolid-state image pickup device, since the photodiode functioning as alight receiving portion is necessarily disposed close to the circuit,the reduction in thickness of the semiconductor layer has to beperformed. In addition, the depth of the opening which exposes the wirelocated at a lower side than the bonding surface is preferably reduced.Hence, when a solid-state image pickup device has an upper semiconductorsubstrate (the first semiconductor substrate in this embodiment) onwhich a pixel array is provided as in this embodiment, the opening ispreferably formed from the side of the first semiconductor substrate,the thickness of which is reduced, to expose the electrode pad portion.

FIG. 21 is a schematic structural view showing a solid-state imagepickup device according to a second embodiment of the present invention.As in FIG. 3, FIG. 21 is a schematic structural view showing an areaincluding a region in which a pad portion is formed. A solid-state imagepickup device 82 of this embodiment shows one structural example inwhich since an inter-substrate wire 80 is formed from one connectionhole, a pixel region and a control circuit at a first semiconductorsubstrate 31 side and a logic circuit at a second semiconductorsubstrate 45 side are electrically connected to each other. In FIG. 21,elements corresponding to those shown in FIG. 3 are designated by thesame reference numerals and descriptions thereof are omitted.

In this embodiment, the inter-substrate wire 80 electrically connectingbetween the first semiconductor substrate 31 and the secondsemiconductor substrate 45 penetrates the first semiconductor substrate31 from a rear surface side thereof and reaches a topmost-layer aluminumwire 57 above the second semiconductor substrate 45. Furthermore, theinter-substrate wire 80 partly reaches a copper wire 40 above the firstsemiconductor substrate 31. In this embodiment, after an insulating filmis formed on an inside wall surface of the connection hole, a conductoris filled in the connection hole, so that the inter-substrate wire 80 isformed which connects the wire at a logic circuit side and the wire at apixel region and a control circuit side.

In addition, in this embodiment, a shading film 63 is formed after theinter-substrate wire 80 is formed. In this case, after theinter-substrate wire 80 is formed, a cap film 72 is formed on an upperportion of the inter-substrate wire 80, and subsequently, the shadingfilm 63 may be formed.

In the solid-state image pickup device of this embodiment, the logiccircuit is electrically connected to the pixel region and the controlcircuit by one inter-substrate wire 80. Hence, compared to the case ofthe first embodiment, the structure is simplified, and the number ofmanufacturing steps can also be reduced. Accordingly, the manufacturingcost can be further reduced. In addition, advantages similar to those ofthe first embodiment can also be obtained.

In the solid-state image pickup device of the above embodiment, althoughthe structure is formed such that electrons are used as the signalcharge, the first conduction type is a p type, and the second conductiontype is an n type, the present invention may also be applied to asolid-state image pickup device in which holes are used as the signalcharge. In this case, the conduction types of respective semiconductorsubstrates, semiconductor well regions, or semiconductor regions arereversed, so that an n type is used as the first conduction type and a ptype is used as the second conduction type.

In the first embodiment described above, although the MOS solid-stateimage pickup device is described by way of example, the presentinvention may also be applied to a semiconductor device. Next, as athird embodiment of the present invention, a semiconductor device inwhich different types of chips are laminated to each other will bedescribed.

With reference to FIG. 22 and FIGS. 23 to 28, a semiconductor deviceaccording to a third embodiment of the present invention and amanufacturing method thereof will be described. A semiconductor device140 of this embodiment is a semiconductor device including a firstsemiconductor substrate 101 on which a first semiconductor integratedcircuit is formed and a second semiconductor substrate 102 on which asecond semiconductor integrated circuit is formed, the first and thesecond semiconductor substrates being laminated to each other. In FIG.22, elements corresponding to those in FIG. 3 are designated by the samereference numerals and descriptions thereof are omitted.

In the third embodiment, first, as shown in FIG. 23, on a region to beformed into each chip portion of the first semiconductor substrate(semiconductor wafer) 101, a semi-finished first semiconductorintegrated circuit, that is, a logic circuit in this embodiment, isformed. That is, on a region to be formed into each chip portion of asemiconductor well region 108 formed in the first semiconductorsubstrate 101 composed of silicon, a plurality of MOS transistors Tr9,Tr10, and Tr11 are formed. The MOS transistors Tr9 to Tr11 are eachformed of source/drain regions 105 and a gate electrode 106 formed on agate insulating film. The MOS transistors Tr9 to Tr11 are isolated fromeach other by an element isolation region 100.

Although a plurality of MOS transistors is formed, in FIG. 23, the MOStransistors Tr9 to Tr11 are shown as representatives thereof. The logiccircuit may be formed by a CMOS transistor. Hence, as the MOStransistors Tr9 to Tr11, an n-channel MOS transistor or a p-channel MOStransistor may be formed. Hence, when an n-channel MOS transistor isformed, n-type source/drain regions are formed in a p-type semiconductorwell region. When a p-channel MOS transistor is formed, p-typesource/drain regions are formed in an n-type semiconductor well region.

In addition, as the first semiconductor integrated circuit, instead ofthe logic circuit a semiconductor memory circuit may also be used. Inthis case, the second semiconductor integrated circuit which will bedescribed later is used as a logic circuit for signal processing of thesemiconductor memory circuit.

In addition, after a second insulating thin film 43 b is formed, as inthe first embodiment, an insulating spacer layer 113 is formed whichisolates a desired region in the semiconductor well region 108 of thefirst semiconductor substrate 101. The insulating spacer layer 113 isformed such that after the second insulating thin film 43 b is formed,an opening is formed in the first semiconductor substrate 101 at adesired position from the rear surface side thereof, and an insulatingmaterial is filled in the opening. This insulating spacer layer 113 is alayer formed in a region surrounding an inter-substrate wire 115 shownin FIG. 22.

Next, a plurality of layers, that is, three layers of copper wires 104in this embodiment, are laminated to each other with interlayerinsulating films 103 interposed therebetween, so that a multilayer wirelayer 107 is formed on the first semiconductor substrate 101. In thisembodiment, although the case in which the wires forming the multilayerwire layer 107 are composed of copper is described by way of example,the metal wire may be formed of another metal material. The multilayerwire layer 107 may be formed in a manner similar to that of the firstembodiment. In addition, the MOS transistors Tr9 to Tr11 are eachconnected to a necessary first-layer copper wire 104 with a connectionconductor 112 interposed therebetween. In addition, the three layers ofcopper wires 104 are connected to each other with the connectionconductors 112 interposed therebetween.

In addition, as shown in FIG. 24, on a region to be formed into eachchip portion of the second semiconductor substrate (semiconductor wafer)102, a semi-finished second semiconductor integrated circuit, that is, alogic circuit, is formed. That is, as in the case shown in FIG. 23, on aregion to be formed into each chip portion of a semiconductor wellregion 116 formed in the second semiconductor substrate 102 composed ofsilicon, a plurality of MOS transistors Tr12, Tr13, and Tr14 is formed.The MOS transistors Tr12 to Tr14 are each formed of source/drain regions117 and a gate electrode 118 formed on a gate insulating film. Inaddition, the MOS transistors Tr12 to Tr14 are isolated from each otherby an element isolation region 127.

Although a plurality of MOS transistors is formed, in FIG. 24, the MOStransistors Tr12 to Tr14 are shown as representatives thereof. The logiccircuit may be formed by a CMOS transistor. Hence, as these MOStransistors, an n-channel MOS transistor or a p-channel MOS transistormay be formed. Accordingly, when an n-channel MOS transistor is formed,n-type source/drain regions are formed in a p-type semiconductor wellregion. When a p-channel MOS transistor is formed, p-type source/drainregions are formed in an n-type semiconductor well region.

Next, a plurality of layers, that is, four layers of metal wires in thisexample, are laminated to each other with interlayer insulating films119 interposed therebetween, so that a multilayer wire layer 124 isformed on the second semiconductor substrate 102. In this embodiment,three layers of copper wires 120 and one layer of an aluminum wire 121as the topmost layer are formed. The MOS transistors Tr12 to Tr14 areeach connected to a necessary first-layer copper wire 120 with aconnection conductor 126 interposed therebetween. In addition, the threelayers of copper wires 120 and the aluminum wire 121 are connected toeach other with the connection conductors 126. Furthermore, also in thisembodiment, barrier metal layers 129 and 130 are formed on the bottomand the top of the aluminum wire 121, respectively, and the aluminumwire 121 is connected to a lower-layer copper wire 120 with the bottombarrier metal layer 129 interposed therebetween. This multilayer wirelayer 124 may be formed in a manner similar to that of the firstembodiment.

In addition, on the multilayer wire layer 124, a stress correction film123 is formed which reduces a stress generated when the firstsemiconductor substrate 101 and the second semiconductor substrate 102are adhered to each other. The stress correction film 123 may also beformed in a manner similar to that of the first embodiment.

Next, as shown in FIG. 25, the first semiconductor substrate 101 and thesecond semiconductor substrate 102 are adhered to each other so that themultilayer wire layer 107 faces the multilayer wire layer 124. Theadhesion is performed using an adhesive. When the adhesion is performedusing an adhesive, an adhesive layer 125 is formed on one adhesionsurface of the first semiconductor substrate 101 or the secondsemiconductor substrate 102, and with this adhesion layer 125, the twosubstrates are overlapped with and secured to each other. In thisembodiment, although the case in which the first semiconductor substrate101 and the second semiconductor substrate 102 are adhered to each otherwith the adhesion layer 125 interposed therebetween is described by wayof example, plasma bonding may also be used for adhesion between the twosubstrates. In the case of plasma bonding, a plasma TEOS film, a plasmaSiN film, a SiON film (block film), a SiC film, or the like is formed oneach of the bonding surfaces of the first semiconductor substrate 101and the second semiconductor substrate 102. The bonding surfacesprovided with the films mentioned above are processed by a plasmatreatment and are then overlapped with each other, and subsequently, anannealing treatment is preformed, so that the two substrates are securedto each other. The adhesion treatment is preferably performed by a lowtemperature process at a temperature of 400° C. or less in which wiresand the like are not adversely influenced. Accordingly, the firstsemiconductor substrate 101 and the second semiconductor substrate 102are laminated and adhered to each other, so that a laminate 140 a formedof the two different types of substrates is formed.

Next, as shown in FIG. 26, the first semiconductor substrate 101 isground and polished from the rear surface side thereof, so that thethickness of the first semiconductor substrate 101 is reduced. When thefirst semiconductor substrate 101 has a thickness of approximately 600μm, the thickness thereof is reduced to approximately 5 to 10 μm.

Next, as shown in FIG. 27, after the thickness of the firstsemiconductor substrate 101 is reduced, by steps similar to those shownin FIGS. 8 to 12 of the first embodiment, an inter-substrate wire 115 isformed in a through substrate via hole and a connection hole formed inthe insulating spacer layer 113 with an insulating layer 114 interposedtherebetween. In this embodiment, since the through substrate via holeand the connection hole are also formed after the thickness of the firstsemiconductor substrate 101 is reduced, the aspect ratio of eachconnection hole is decreased, and hence the connection holes can be eachformed as a fine hole. In addition, by the inter-substrate wire 115, thecircuit formed on the first semiconductor substrate 101 is electricallyconnected to the circuit formed on the second semiconductor substrate102. Subsequently, in a manner similar to that of the first embodiment,a cap film 72 is formed on the entire surface including theinter-substrate wire 115.

Next, as shown in FIG. 28, a resist film 143 having an opening at anelectrode pad portion 142 shown in FIG. 22 is formed. In addition,etching is performed by using the resist film 143 as a mask to form athrough substrate opening portion 132 penetrating the firstsemiconductor substrate 101, so that the aluminum wire 121 is exposed.Hence, the electrode pad portion 142 is formed from the exposed aluminumwire 121. In addition, in this embodiment, as shown in FIG. 20, grooveportions each functioning as a crack stopper are also simultaneouslyformed at two sides of a scribe line when the through substrate openingportion 132 is formed. Subsequently, the laminate thus obtained isdivided into chips, so that the semiconductor device 140 of thisembodiment shown in FIG. 22 is completed.

In each chip obtained by this division, as shown in FIG. 22, a bondingwire 131 is connected to the electrode pad portion 142, therebyconnecting the electrode pad portion 142 to an external wire of amounting substrate. In addition, since the electrode pad portion 142 iselectrically connected to the external wire, the multilayer wire layers107 and 124 on the first semiconductor substrate 101 and the secondsemiconductor substrate 102, respectively, which are connected to eachother by the inter-substrate wire 115, are also electrically connectedto the external wire.

In the semiconductor device 140 according to the third embodiment andthe manufacturing method thereof, as in the case described above, thefirst semiconductor integrated circuit and the second semiconductorintegrated circuit can be formed on different chip portions by usingoptimal process techniques, and hence a high performance semiconductorintegrated circuit can be provided. In addition, chips in a finishedproduct state are formed after the semi-finished first and the secondsemiconductor wafers are adhered to each other, the thickness of one ofthe wafers is reduced, and the first and the second semiconductorintegrated circuits are electrically connected to each other; hence, themanufacturing cost can be reduced.

Furthermore, advantages similar to those of the first embodiment canalso be obtained.

The above solid-state image pickup device according to an embodiment ofthe present invention may be applied to an electronic apparatusincluding a camera system, such as a digital camera or a video camera, amobile phone having an image pickup function, and another apparatushaving an image pickup function.

In FIG. 29, a schematic structural view of an electronic apparatusaccording to a fourth embodiment of the present invention is shown. FIG.29 shows a camera 200 by way of example as the electronic apparatusaccording to an embodiment of the present invention. The camera 200 ofthis embodiment is a camera capable of taking a still image or a motionpicture. The camera 200 of this embodiment includes a solid-state imagepickup device 203, an optical system 201 guiding incident light to aphotoelectric conversion portion formed of a photodiode of thesolid-state image pickup device 203, and a shutter device 202.Furthermore, the camera 200 includes a drive circuit 205 driving thesolid-state image pickup device 203 and a signal processing circuit 204processing an output signal of the solid-state image pickup device 203.

For the solid-state image pickup device 203, one of the solid-stateimage pickup devices according to the first and the second embodimentsis used. The optical system (optical lens) 201 forms an image on animage surface of the solid-state image pickup device 203 by image light(incident light) from an object. Accordingly, a signal charge is storedin the solid-state image pickup device 203 for a predetermined period.The optical system 201 may be an optical lens system formed of aplurality of optical lenses. The shutter device 202 controls a lightradiation period and a light shielding period for the solid-state imagepickup device 203. The drive circuit 205 supplies drive signals tocontrol a transfer motion of the solid-state image pickup device 203 anda shutter motion of the shutter device 202. By a drive signal (timingsignal) supplied from the drive circuit 205, signal transfer of thesolid-state image pickup device 203 is performed. The signal processingcircuit 204 performs various types of signal processings. An imagesignal treated by signal processing is stored in a storage medium, suchas a memory, or is output on a monitor.

According to the electronic apparatus, such as the camera 200, of thefourth embodiment, improvement in performance can be performed by thesolid-state image pickup device 203, and in addition, the manufacturingcost can be reduced. Hence, in this embodiment, a highly reliableelectronic apparatus can be provided at an inexpensive price.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. An imaging device comprising: a firstsemiconductor section including a first multilayer wiring layer at oneside thereof, the first semiconductor section further including aplurality of pixel units arranged in a two-dimensional array, and eachpixel unit of the plurality of pixel units including a photodiode and atleast one transistor; a second semiconductor section including a secondmultilayer wiring layer at one side thereof, the first and secondsemiconductor sections being secured together with a bonding layerbetween the first and second multilayer wiring layers such that therespective first and second multilayer wiring layers of the first andsecond semiconductor sections face each other; a first conductorextending through the first semiconductor section and the bonding layerto a first portion of the second multilayer wiring layer of the secondsemiconductor section and electrically interconnecting a wiring of thefirst multilayer wiring layer with a wiring of the second multilayerwiring layer; a second conductor extending through the firstsemiconductor section and the bonding layer to a second portion of thesecond multilayer wiring layer of the second semiconductor section andelectrically interconnecting the wiring of the second multilayer wiringlayer with an external wire, wherein, the first portion and the secondportion of the second multilayer wiring layer are disposed at a samelayer.
 2. The imaging device of claim 1, wherein the first conductorincludes a metal material.
 3. The imaging device of claim 2, wherein themetal material includes tungsten (W).
 4. The imaging device of claim 1,wherein the second conductor includes a metal material.
 5. The imagingdevice of claim 1, wherein the second conductor includes one or more ofa bonding wire or a solder bump.
 6. The imaging device of claim 1,wherein the first conductor and the second conductor are disposed in aperipheral region around the plurality of pixel units.
 7. The imagingdevice of claim 1, wherein the first conductor is disposed in a grooveportion and the first conductor contacts an insulating layer at a sidewall of the groove portion.
 8. The imaging device of claim 1, whereinthe first conductor is disposed between a first part of an insulatingspacer layer and a second part of the insulating spacer layer in across-sectional view.
 9. The imaging device of claim 1, wherein thesecond wiring layer includes a barrier metal layer.
 10. The imagingdevice of claim 9, wherein the barrier metal layer includes one or moreof TiN, Ti, TaN, or Ta.
 11. The imaging device of claim 1, wherein thebonding layer includes an adhesive layer.
 12. The imaging device ofclaim 1, wherein the bonding layer includes one or more of a plasma TEOSfilm, a plasma SiN film, a SiON film, or a SiC film.
 13. The imagingdevice of claim 1, further comprising: a stress reduction film disposedbetween the first semiconductor section and the second semiconductorsection.
 14. The imaging device of claim 1, wherein a first pixel unitis separated from a second pixel unit by an isolation region.
 15. Theimaging device of claim 14, wherein the first conductor is disposedbetween a first part of the isolation region and a second part of theisolation region.
 16. The imaging device of claim 15, wherein theisolation region contacts a third part of an insulating spacer layer inthe cross-sectional view.
 17. The imaging device of claim 1, furthercomprising: a planarization film disposed above the first semiconductorsection.
 18. The imaging device of claim 1, further comprising: atransfer transistor coupled to the photodiode in the first semiconductorsection.
 19. The imaging device of claim 18, wherein the transfertransistor is coupled to the first multilayer wiring layer.
 20. Theimaging device of claim 19, further comprising: an on-chip lens and anon-chip color filter disposed above the photodiode.
 21. The imagingdevice of claim 19, wherein a drain or source region of the transfertransistor is a floating diffusion in the first semiconductor section.22. The imaging device of claim 19, further comprising: a gate electrodedisposed in the first semiconductor section.
 23. An apparatuscomprising: an imaging device comprising: a first semiconductor sectionincluding a first multilayer wiring layer at one side thereof, the firstsemiconductor section further including a plurality of pixel unitsarranged in a two-dimensional array, and each pixel unit of theplurality of pixel units including a photodiode and at least onetransistor, a second semiconductor section including a second multilayerwiring layer at one side thereof, the first and second semiconductorsections being secured together with a bonding layer between the firstand second multilayer wiring layers such that the respective first andsecond multilayer wiring layers of the first and second semiconductorsections face each other, a first conductor extending through the firstsemiconductor section and the bonding layer to a first portion of thesecond multilayer wiring layer of the second semiconductor section andelectrically interconnecting a wiring of the first multilayer wiringlayer with a wiring of the second multilayer wiring layer; a secondconductor extending through the first semiconductor section and thebonding layer to a second portion of the second multilayer wiring layerof the second semiconductor section and electrically interconnecting thewiring of the second multilayer wiring with an external wire, whereinthe first portion and the second portion of the second multilayer wiringlayer are disposed at a same layer; and at least one lens disposed abovethe imaging device.